Clutch paranoia or something more?

[JFratzke]

So I had my auto body guy fix my rear fender yesterday and it turned out perfect. He also covered the area with his Rhinoliner to show me that he could do it (I had mentioned I was going to have another shop do it). Looks outstanding and he definately earned the rhinolining work too (going to have the van rhinoed from the top of the lower molding down). BUT, when he drove it back to me, he asked me if I knew that my clutch was 'slipping'. I hadn't noticed. So now I am paranoid about it, bigtime. I have already been into the tranny (replaced severely damaged bell housing) and my mechanic said the clutch looked fine. I just had the slave and the master done two weeks ago. I did pull a hill shortly after that where I felt like the clutch was slipping (engine would over rev after a shift without increased power, but then 'catch') but it didn't do it that bad and felt normal as soon as I made it over the pass. I had a buddy drive it yesterday and he said my engagement point was too close to top of the pedal's arc. He said it should engage shortly after I release the clutch from the floor, say 3-4 inches off the floor. Instead, it does its thing just before my foot is completely off the clutch. Help. I am not super excited about doing the clutch since my mechanic told me it was fine. I looked at the adjustment bolt above the pedal last night and it looks straight forward enough to mess with, I just don't know if I should let more of the bolt out or crank it in . Not even sure if doing either would help. So what does it sound like to the community? Should I order a new clutch and the other parts Tim recommends changing with the clutch or would a simple adjustment help out here?

[timsrv]

To test the clutch get the van going about 20 MPH, put the transmission in 4th gear, rev the engine high and dump the clutch. Mash the accelerator to the floor while dumping the clutch. If the engine continues to rev then your clutch has a problem. If the clutch can drag the engine down and make it lug, then the clutch is fine. If you think it's out of adjustment then use the service manual to adjust. The clutch section outlines the procedure. Tim

[JFratzke]

The clutch passed the test, and it definitely will hold the motor back when you downshift, so it seems to be fine. I called the shop that did the master and the slave and they said they would re-bleed the clutch and do the adjustment for free. Score! I also visited with the tech who did the bell housing and he said that everything in there looked mechanically a-ok. He said he checked it thouroughly because he wanted to do the clutch as long as he was in there, but there was nothing he could hang his hat on to justify doing it. So I am going to have it bled and adjusted and just go from there. I have a short mountain drive planned for wednesday that includes a pretty steep uphill grade so that will be a good opportunity to check it out again. And we will have a great day in the mountains too!

[JFratzke]

Shop just called and said that the clutch slave cylinder they put in two weeks ago is leaking, bigtime. Bingo--that should be the cause of the slippage, right? Part is under warranty, as is the work to re-installed the new one. Only bummer is that my van will be sitting in the shop over the fourth instead of having a great time with me!

[wirewrkr]

If the slave cylinder is bad, I cannot see how that is going to contribute to slipping. Only poor ability to shift.
It's good that they are replacing it and all that, but to blame that for the slipping?
It would have had to have "hung up" and not fully disengaged
There are a handfull of things that can cause "slipping"
As follows:
1) A worn clutch disc and/or damage and wear to other related friction parts.
2) bad pressure plate spring(s)
2) A clutch disc that has become contaminated with some foreign fluid, such as engine oil, transmission oil etc.
3) Rare,(but has happened), Splines on the input shaft of transmission are dry as a bone and or scored, causing the disc to hang-up and not move freely.
4) throwout bearing (also rare) has partially come undone and is jamming the clutch spring fingers in the pressure plate causing uneven pressure on the disc.
5) Driver resting foot on the clutch pedal. ( seen this one more than once!)

[timsrv]

[wirewrkr]

Once upon a time I was restoring an old SAAB 96 with a V4 engine.
Had the engine out to rebuild it, and all the clutch components looked excellent, so they were re-used.
In the process of re-installing the pressure plate, it gave up the ghost. Of course I didn't find that out until AFTER I reinstalled the engine and attempted to drive it.
I've seen clutch springs do that more than once. In each occurrence, the vehicle in question had sat dormant for several years. Some say that the springs took a "set" from sitting
for so long in one position and not being flexed.
Just sayin'

[JFratzke]

Well, replacing the slave made a big difference. The clutch now engages at 3 in off the floor instead of at the very top of the travel of the pedal. I think before it wasn't fully engaging, thereby allowing a little slippage to occur. It shifts much cleaner now and accelerates much smoother and faster. I went ahead and ordered everything to do the clutch but I am going to put it in a box and do it when I am convinced it needs it. For now, everything seems to be working just fine. Thanks for the input everyone!

[JFratzke]

After rereading this thread, I'd just like to point out the in the end, wirewker was correct--the real seal was leaking oil down into the transmission all over the clutch, causing the slippage that we felt. Replaced the clutch components and the rear seal and haven't had any problems since. Just wanted to give credit where credit was due....